1) Welcome to the Party!
2) As you are obviously new here, I have some suggestions to help us all help you:
When you post, please post your entire configuration including (but not limited to) your installation method (7.X.X?) and vicidial version with build (VERSION: 2.X-XXXx ... BUILD: #####-####).
This IS a requirement for posting along with reading the stickies (at the top of each forum) and the manager's manual (available on EFLO.net, both free and paid versions)
You should also post: Asterisk version, telephony hardware (model number is helpful here), cluster information if you have one, and whether any other software is installed in the box. If your installation method is "manual/from scratch" you must post your operating system with version (and the .iso version from which you installed your original operating system) plus a link to the installation instructions you used. If your installation is "Hosted" list the site name of the host.
If this is a "Cloud" or "Virtual" server, please note the technology involved along with the version of that techology (ie: VMware Server Version 2.0.2). If it is not, merely stating the Motherboard model # and CPU would be helpful.
Similar to This:
Vicibox X.X from .iso | Vicidial X.X.X-XXX Build XXXXXX-XXXX | Asterisk X.X.X | Single Server | No Digium/Sangoma Hardware | No Extra Software After Installation | Intel DG35EC | Core2Quad Q6600
3) To be clear: Vicidial doesn't have a "v8", but Vicibox does. Vicibox is the Installer. ViciDIAL is the call center/dialer suite (the actual software), which runs in the Environment constructed by the installer. Two separate things, providing the full version information for both is the best way to go when asking for assistance.
4) Retransmission means the connection failed. Many reasons can be found for this (all of which have been posted many times on this forum, if you want to do a search and read up). Summary: Likely Gonna be firewall related. Either your firewall is blocking inbound return packets from your VOIP company or they are simply not responding OR they are sending malformed packets. /etc/asterisk/sip.conf has a value "externip" which must be set to the Public IP of the server (if not sure: type "curl ip.whowebwhere.com" and you'll get the public ip). Reloading or restarting asterisk may be necessary after changing this value. That IP address controls where packets are sent by the SIP engine, so if that value is a local IP or the wrong IP, the control packets will be sent to the wrong location and you'll never get 'em. One solution is a public IP directly to the server and use the yast firewall (iptables) to whitelist lockdown the server instead of using an external firewall with a shared IP address. Not required, but often makes the problem go away with less hair pulling.